From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52973C3F2CD for ; Fri, 28 Feb 2020 17:49:29 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 18F72246A3 for ; Fri, 28 Feb 2020 17:49:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="TcQ18XKV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 18F72246A3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=NT591aerAPAg2guo/aTNT5eAhGrZIXybydZCAtHJvxA=; b=TcQ18XKVXTZvOt IjNQaqX8uXDTzKOYwA8xwsiBCPscPXg3TMEpBuQK7VlO1YXYtg9ZMhmhaAUzD/GT5ICJgigrNA/we PTwAGGdYnFC/dv0vVX84TTxRq6Sl+AyfWL/MvdGslb+IDRVLofjZrw3BQsz/wpzeVu8pD4IuzeyWL h5dNOKtT07U9O8nCTAexFMVWIFfOC8qULZ0ltnTOG+sSSLbf+jTEYgCBM7/jxGRpJRjJZ9tXuq5yW Pi9xJxOjtmty/4OGSsM031mdEDalviobR//ZqTQw3lscqDByDpZjHpey2iOh2mcoejo/MOfI+wzzO p1daOSqgwip2NS2ssbFw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1j7jlH-00086z-HT; Fri, 28 Feb 2020 17:49:19 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1j7jkZ-0007Wb-1Y for linux-arm-kernel@lists.infradead.org; Fri, 28 Feb 2020 17:48:36 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 731E331B; Fri, 28 Feb 2020 09:48:34 -0800 (PST) Received: from eglon.cambridge.arm.com (eglon.cambridge.arm.com [10.1.196.105]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8FB4D3F7B4; Fri, 28 Feb 2020 09:48:32 -0800 (PST) From: James Morse To: linux-mm@kvack.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 3/3] arm64: acpi: Make apei_claim_sea() synchronise with APEI's irq work Date: Fri, 28 Feb 2020 17:48:17 +0000 Message-Id: <20200228174817.74278-4-james.morse@arm.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200228174817.74278-1-james.morse@arm.com> References: <20200228174817.74278-1-james.morse@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200228_094835_186118_C958C63B X-CRM114-Status: GOOD ( 17.61 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Tony Luck , Xie XiuQi , Catalin Marinas , Rafael Wysocki , Tyler Baicar , Borislav Petkov , James Morse , Andrew Morton , Will Deacon , Naoya Horiguchi , Len Brown Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org APEI is unable to do all of its error handling work in nmi-context, so it defers non-fatal work onto the irq_work queue. arch_irq_work_raise() sends an IPI to the calling cpu, but this is not guaranteed to be taken before returning to user-space. Unless the exception interrupted a context with irqs-masked, irq_work_run() can run immediately. Otherwise return -EINPROGRESS to indicate ghes_notify_sea() found some work to do, but it hasn't finished yet. With this apei_claim_sea() returning '0' means this external-abort was also notification of a firmware-first RAS error, and that APEI has processed the CPER records. Signed-off-by: James Morse --- Changes since $last_year: * Dropped all the tags ... its been a year. * Added user_mode() test in do_sea() and expanded the comment. * Dont depend on daif value for return_to_irqs_enabled because of pNMI. * pr_warn() should be ratelimited --- arch/arm64/kernel/acpi.c | 25 +++++++++++++++++++++++++ arch/arm64/mm/fault.c | 12 +++++++----- 2 files changed, 32 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index a100483b47c4..46ec402e97ed 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -269,6 +270,7 @@ pgprot_t __acpi_get_mem_attribute(phys_addr_t addr) int apei_claim_sea(struct pt_regs *regs) { int err = -ENOENT; + bool return_to_irqs_enabled; unsigned long current_flags; if (!IS_ENABLED(CONFIG_ACPI_APEI_GHES)) @@ -276,6 +278,12 @@ int apei_claim_sea(struct pt_regs *regs) current_flags = local_daif_save_flags(); + /* current_flags isn't useful here as daif doesn't tell us about pNMI */ + return_to_irqs_enabled = !irqs_disabled_flags(arch_local_save_flags()); + + if (regs) + return_to_irqs_enabled = interrupts_enabled(regs); + /* * SEA can interrupt SError, mask it and describe this as an NMI so * that APEI defers the handling. @@ -284,6 +292,23 @@ int apei_claim_sea(struct pt_regs *regs) nmi_enter(); err = ghes_notify_sea(); nmi_exit(); + + /* + * APEI NMI-like notifications are deferred to irq_work. Unless + * we interrupted irqs-masked code, we can do that now. + */ + if (!err) { + if (return_to_irqs_enabled) { + local_daif_restore(DAIF_PROCCTX_NOIRQ); + __irq_enter(); + irq_work_run(); + __irq_exit(); + } else { + pr_warn_ratelimited("APEI work queued but not completed"); + err = -EINPROGRESS; + } + } + local_daif_restore(current_flags); return err; diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 85566d32958f..cefeb34580da 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -645,11 +645,13 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs) inf = esr_to_fault_info(esr); - /* - * Return value ignored as we rely on signal merging. - * Future patches will make this more robust. - */ - apei_claim_sea(regs); + if (user_mode(regs) && apei_claim_sea(regs) == 0) { + /* + * APEI claimed this as a firmware-first notification. + * Some processing deferred to task_work before ret_to_user(). + */ + return 0; + } if (esr & ESR_ELx_FnV) siaddr = NULL; -- 2.24.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel